I recently had the opportunity to explore Old Town Alexandria in Virginia. It was full of the most charming colonial row houses and I could not resist putting one in my game.
Old Town Apartments is a single residence made up of 3 completely separate apartments. With the ability to lock doors, you can decide for yourself which sims live where....but I envision this as a great legacy kind of home. You could have the elders living in one apartment, the main family in the larger, center unit, and the newlyweds in the smallest "starter" style unit.
The townhomes come with:
9 bedrooms (all very spacious)
large hobby room
30x40 lot size ( plenty of extra room in back for large items like the telescope or rocket kit)
The largest apartment is a bit more formal and includes a formal dining room.
Apartment 1 is contemporary
Apartment 3 is the smallest and more modern in feel